Go Web Application Http Test

Http Test

Go Unit Test explains how to use test package and test simple json handle functions.

Next target is to test http request and response. (web application)

Steps

This is the step to write test

1. Create multiprexor
2. Add handler
3. Create recorder
4. Create request
5. Record into recorder
6. Check

Example

At first, let’s create simple API (handler)

simplemethodhandler.go

package web

import (
	"errors"
	"fmt"
	"net/http"
	"path"
	"strconv"
)

func handleRequest(w http.ResponseWriter, r *http.Request) {
	var err error
	switch r.Method {
	case "GET":
		err = handleGet(w, r)
	case "POST":
		err = errors.New("Not Support")
	case "PUT":
		err = errors.New("Not Support")
	case "DELETE":
		err = errors.New("Not Support")
	}

	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
}

func handleGet(w http.ResponseWriter, r *http.Request) (err error) {
	id, err := strconv.Atoi(path.Base(r.URL.Path))
	if err != nil {
		return
	}
	fmt.Println(id)
	w.Header().Set("Content-Type", "application/json")
	w.Write([]byte("{\"id\":1}"))
	return
}

This is simple handler

To support only GET request and others are mock.

GET request returns simple json data

Next is test

simplemethodhandler_test.go

Same as last entry, file name is xxxx_test.go

package web

import (
	"net/http"
	"net/http/httptest"
	"os"
	"testing"
)

var mux *http.ServeMux
var writer *httptest.ResponseRecorder

func TestMain(m *testing.M) {
	setUp()
	code := m.Run()
	os.Exit(code)
}

func setUp() {
	// Set up common functions
	mux = http.NewServeMux()
	mux.HandleFunc("/get/", handleRequest)
	writer = httptest.NewRecorder()
}

func TestHandleGet(t *testing.T) {

	request, _ := http.NewRequest("GET", "/get/1", nil)
	mux.ServeHTTP(writer, request)
	if writer.Code != 200 {
		t.Errorf("Response code is %v", writer.Code)
	}
}

func TestMain(m *testing.M) is common function for test methods, if there are multiple tests in, this is called at first. We will write common part here.

In this example, prepare mux and recorder

Actual test is under func TestXxxxx.

Create request and call ServeHTTP method, and check response. If response is not 200, create error.